Commendable

Hey there, I've been wanting to upgrade my i3 7100 for a longer time now and I've been looking for a better replacement for it and I found out about the Intel's 8th gen i5 8400. How would this processor perform in comparison to my i3 7100 in gaming? I usually play newer titles such as PUBG or F1 2018. I have a ASUS B250M motherboard and I was wondering if the 8400 is compatible with it? The GPU I have is a RX 470.

There are, but the prices for 6th/7th gen parts (the ones that would work with your board) are pretty awful given how they perform relative to newer parts, so you're often better off upgrading CPU + mobo. Unless you can find a good deal on used parts.

For example, a quad core i5 7500 is $200 new. For that price you could get an equivalent quad core i3 8100 and a new motherboard, and that new motherboard would allow you to eventually upgrade to a 6 core/12 thread CPU (technically up to a 8core/16thread, but I don't know if I'd run an 8 core CPU on a low end motherboard).

Or if you went with Ryzen, you could get a 6 core/12 thread CPU and motherboard for ~$200.

Commendable

There are, but the prices for 6th/7th gen parts (the ones that would work with your board) are pretty awful given how they perform relative to newer parts, so you're often better off upgrading CPU + mobo. Unless you can find a good deal on used parts.

For example, a quad core i5 7500 is $200 new. For that price you could get a quad core i3 8100 and a new motherboard, and that new motherboard would allow you to eventually upgrade to a 6 core/12 thread CPU (technically up to a 8core/16thread, but I don't know if I'd run an 8 core CPU on a low end motherboard).

Or if you went with Ryzen, you could get a 6 core/12 thread CPU and motherboard for ~$200.